Non-lethal projectiles can be lethal at close ranges and ineffective at further ranges and are difficult for use in engaging a target if the distance to the target is unknown. Further, some non-lethal projectiles have significant drop at longer distances because they often travel at lower velocities than lethal projectiles making them less accurate without proper range adjustments for drop of the projectile. Many projectile launchers are used for both non-lethal and lethal projectiles. Therefore, it is important to know the range of the target to adjust for drop and lethality before firing a non-lethal projectile. In order to accurately adjust for the drop of a non-lethal round, the shooter must know the distance to the target. Once the range is determined, the user can insure both accuracy and lethality parameters are being met considering the distance to the target. The accuracy of a non-lethal projectile can be the difference between life and death. Most non-lethal projectiles are designed to hit the body or limbs to incapacitate a subject and a head shot can cause fatal or substantial injury. Thus by ranging the target and accounting for projectile drop over the distance, the probability of an unintended lethal shot is drastically reduced.
Current M203 or M302 military 40 mm grenade launchers use a mechanical flip-up sighting system that is inaccurate and non-ergonomic. In a lethal/non-lethal combination weapon, the grenade launcher mounts under a military rifle such as an M16 or M4. Because lethal and less lethal rounds will be shot at different distances and velocities a mechanical sight is impractical and will not accommodate varying projectile paths. Further, the weight of the lethal and non-lethal projectiles is significantly different which makes the projectile flight paths significantly different from one another. Consequently, a need exists for a ranging and sighting system capable for use, for both lethal and non-lethal projectile launcher weapons.